soc/intel/common/block/fast_spi: Add SPI BIOS decode lock

The SPI BIOS decode lock bit needs to be set, according to
Intel EBG EDS dodcumentation.

Signed-off-by: Tim Chu <Tim.Chu@quantatw.com>
Change-Id: I3366817b42a5878f16575698ebc546fa7852e285
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71953
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jonathan Zhang <jonzhang@fb.com>

src/soc/intel/common/block/fast_spi/fast_spi.c

@@ -457,6 +457,13 @@ void fast_spi_disable_wp(void)
 	pci_write_config8(dev, SPI_BIOS_CONTROL, bios_cntl);
 }
 
+void fast_spi_set_bde(void)
+{
+	const pci_devfn_t dev = PCH_DEV_SPI;
+
+	pci_or_config32(dev, SPI_BIOS_DECODE_EN, SPI_BIOS_DECODE_LOCK);
+}
+
 void fast_spi_clear_outstanding_status(void)
 {
 	void *spibar = fast_spi_get_bar();

src/soc/intel/common/block/fast_spi/fast_spi_def.h

@@ -4,6 +4,8 @@
 #define SOC_INTEL_COMMON_BLOCK_FAST_SPI_DEF_H
 
 /* PCI configuration registers */
+#define SPI_BIOS_DECODE_EN		0xd8
+#define  SPI_BIOS_DECODE_LOCK		BIT(31)
 
 #define SPI_BIOS_CONTROL		0xdc
 

src/soc/intel/common/block/include/intelblocks/fast_spi.h

@@ -103,5 +103,9 @@ uint32_t soc_get_spi_psf_destination_id(void);
  */
 struct postcar_frame;
 void fast_spi_cache_ext_bios_postcar(struct postcar_frame *pcf);
+/*
+ * Set FAST_SPIBAR BIOS Decode Lock bit
+ */
+void fast_spi_set_bde(void);
 
 #endif	/* SOC_INTEL_COMMON_BLOCK_FAST_SPI_H */